ALTERATIONS OF THE RED CORPUSCLES. 385 



been drawn, so that it is difficult to determine whether they 

 are pre-existent in it, whilst it is still circulating, or not. It is 

 certain that, in blood abstracted from healthy persons, in many 



Fig. 69. 



instances, nearly all the corpuscles undergo this alteration, and 

 this is stated (by Max Schultze)* to occur with still greater 

 rapidity in those suffering from febrile diseases. The corpuscles 

 thus altered have been described as mulberry-shaped, and the 

 phenomenon regarded as a stellate contraction of the corpuscle. 

 It was well known, long ago, to Hewson.*f 



The evaporation of water, and perhaps the cooling of the 

 blood, are conditions favourable to these changes. But they 

 may also occur, as will hereafter be shown, even when such 

 conditions are not present. The appearances are presented by 

 the corpuscles of Mammals, as well as by those of Man. And 

 analogous phenomena are occasionally, though rarely, presented 

 by the elliptical and nucleated corpuscles. 



The blood corpuscles of Salamandra maculata, and of Triton 

 cristatus and tseniatus easily assume a mulberry-like form under 

 the microscope. In the blood of the Frog the phenomena 

 first make their appearance as a consequence of the operation 

 of external agents, and the corpuscles then become exactly 

 similar to those of Mammals. 



2. From the action of mechanical agents on the blood 

 corpuscles we learn that their substance is composed of an 

 extremely extensible and, within wide limits, completely 

 elastic material. 



That the blood corpuscles become elongated in their passage 

 through the vessels, and that they also become curved in tra- 



* Loc. cit. 



f Opus posthumum, pp. 19, 20. 



